1.1　Incidence and Prevalence

The changing incidence and prevalence of CP over time worldwide is presented in Table 3.1（Levy et al.2014；Jupp et al.2010）.Reported incidence in the USA was 1.9，4.2，and 3.5 cases per 100,000 people in 1940s，1950s，and 1960s，respectively（Osullivan et al.1972）.A nationwide survey in England and Wales showed increasing incidence of CP from 0.83 cases per 100,000 people in the early 1960s to 3.18 cases per 100,000 people in the early 1980s（Johnson and Hosking 1991）.Another study reported the incidence of CP in England was 4.3 cases per 100,000 people in the years between 1989 and 1990，and 8.6 cases per 100,000 people in the years between 1999 and 2000（Tinto et al.2002）.The incidence and prevalence of CP was 4.0-4.2 cases per 100,000 people，and 13.0 to 14.4/100,000 persons in Denmark surveyed from 1978 to 1979，respectively（Andersen et al.1982）.CP is also widely prevalent in Asia.Both the incidence and the prevalence of CP increased during the 17 years from 1994 to 2011 in Japan（Hirota et al.2012，2014；Otsuki and Tashiro 2007）.The annual incidence and prevalence was 5.4 and 28.5 per 100,000 in the third nationwide survey conducted in Japan in 1994，respectively.The incidence increased to 5.8 per 100,000 in the fourth nationwide survey conducted in 1999，while the prevalence was 32.9 per 100,000.The fifth survey reported the incidence and prevalence increased to 14.4 and 35.5 per 100,000 in 2002，respectively.The sixth nationwide survey in 2007 showed an incidence rate of 11.9 cases per 100,000 persons and a prevalence rate of 36.9 cases per 100,000 population.The estimated annual incidence and prevalence of CP in Japan from the seventh nationwide survey in 2011 was 14.0/100,000 and 52.4/100,000，respectively.

Table 3.1　The changing worldwide incidence and prevalence of chronic pancreatitis overtime（Levy et al.2014；Jupp et al.2010）

N/A data not available
aSingle centre；all patients with chronic pancreatitis
bNational statistics for admissions with chronic pancreatitis
cMulticentre or nationwide survey of all patients with chronic pancreatitis
dSingle centre；all patients admitted with chronic pancreatitis(https://www.daowen.com)

A multicenter survey was conducted in 22 hospitals in 6 urban health care regions of China to determine the nature and magnitude of chronic pancreatitis between May 1994 and April 2004（Wang et al.2009）.The results showed the prevalence of CP was increasing year by year.It was 3.08，3.91，5.28，7.61，10.43，11.92，12.84，and 13.52 per 100,000 inhabitants respectively in the 8 years between 1996 and 2003.In addition，in the six health care areas，whichwere different in economy and life habits，the CP prevalence was increasing at different rates.The prevalence of the east，which was the most developed area，was growing the fastest.It was increasing from 3.27 per 100,000 inhabitants in 1996 to 13.73 per 100,000 inhabitants in 2003.From 1996 to 2003，the CP prevalence in the north of China was 2.93，3.88，4.99，6.89，9.95，11.47，12.78 and 13.05 per 100,000 inhabitants.The prevalence of CP was 2.97 per 100,000 inhabitants in the northeast of China，2.94 per 100,000 inhabitants in thenorthwest of China，2.67 per 100,000 inhabitants in the middle south of China，2.55 per 100,000 inhabitants in the southwest of China in 1996.It increased to 13.12 per 100,000 inhabitants in the northeast of China，12.92 per 100,000 inhabitants in thenorthwest of China，11.62 per 100,000 inhabitants in the middle south of China，12.61 per 100,000 inhabitants in the southwest of China in 2003.